Stochastic Nature of Particle Collisions and its Impact on Granular Material Properties
Stochastic Nature of Particle Collisions and its Impact on Granular Material Properties
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粒子碰撞的随机性质及其对颗粒材料特性的影响
DOI：
10.1007/978-3-030-15899-6_18
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发表时间：
2019
期刊：
影响因子：
--
通讯作者：
T. Pöschel
中科院分区：
文献类型：
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作者：
N. Gunkelmann;D. Serero;Aldo Glielmo;Marina Montaine;Michael Heckel;T. Pöschel
快速颗粒流的动力学由颗粒之间以及颗粒与系统壁之间的耗散相互作用所控制。为了充分描述这些相互作用，必须考虑粗糙度和颗粒形状。因此，任意颗粒的恢复系数不仅取决于材料性质和碰撞速度，而且还取决于碰撞瞬间的角取向。通过测量球体在地面上反复弹跳发出的声音信号的恢复系数，发现与球体完美形状的微小偏差会导致较大的测量误差。利用随机方法，将粗糙球与平面碰撞的有效恢复系数描述为一个波动量，其特征在于一个相当不寻常的概率密度函数。结果表明，建模的恢复系数作为一个随机变量显着影响快速颗粒流下的颗粒的动力学。在均匀冷却状态的快速颗粒流的温度衰减偏离哈夫定律的气体颗粒通过一个常数系数的恢复相互作用也从标度律的气体粘弹性颗粒。
The dynamics of rapid granular flows is governed by dissipative interactions of particles with each other and with the system walls. To adequately describe these interactions, roughness and particle shape must be taken into account. The coefficient of restitution for arbitrary particles thus depends not only on material properties and impact velocity but also on the angular orientation at the instant of the collision. By measurements of the coefficient of restitution from the sound signal emitted by a sphere bouncing repeatedly off the ground, it was found that small deviations from the perfect shape of the sphere lead to large measurement errors. Using stochastic methods, the effective coefficient of restitution for the collision of a rough sphere with a plane was described as a fluctuating quantity, characterized by a rather uncommon probability density function. It was shown that modelling the coefficient of restitution as a stochastic variable significantly affects the dynamics of particles under rapid granular flows. The decay of temperature of rapid granular flows in the homogeneous cooling state deviates from Haff’s law for gases of particles interacting via a constant coefficient of restitution also from the scaling law for gases of viscoelastic particles.